Polymerization of olefinic hydrocarbons



Patented Jan. 14, 1947' POLYMERIZATION OF OLEFINIC HYDROCARBONS Carl B. Linn, Riverside, Ill., assignor to Universal Oil Products Company, Chicago,.lll., a corporation of Delaware No Drawing. Application March 31, 1945,

Serial No. 586,018

8 Claims. (Cl. 260-68315) This application is a continuation-in-part of my copending application Serial No. 424,784, filed December 29, 1941, now Patent Number 2,398,905, granted April 23, 1946, and of my copending 1 application Serial No. 502,664, filed September 16, 1943, now Patent Number 2,406,086, granted August 20, 1946.

This invention relates to the polymerization of olefinic hydrocarbons in the presence of a special type of catalyst. More particularly, this invention relates to the polymerization of propylene and butylenes into normally liquid hydrocarbons boiling within the approximate range of gasoline.

'An object of this invention is to polymerize olefinic hydrocarbons in the presence of a liquid catalytic material."

Another object of this invention is to convert propylene and butylenes into normally liquid hydrocarbons in the presence of a liquid catalyst.

One specific embodiment of this invention relates to a process which comprises reactingan olefinic hydrocarbon having'at least 3 carbon atoms per molecule at polymerizing conditions in the presence of a mixture of hydrogen fluoride and hydrogen cyanide.

Another embodiment of this invention relates to a polymerization process which comprises reacting anormally gaseous olefin containing at least 3 carbon atoms per molecule at polymerizing conditions in the presence of hydrogen fluoride and hydrogen cyanide.

Normally gaseous and liquid olefinic hydro-- carbons which are polymerizable by the process.

of the present invention occur together with parafflnic or saturated hydrocarbons in commercial hydrocarbon mixtures such as those encountered in the cracking of petroleum, in gas making processes, and as by-products of various chemical industries. Suitable olefins, such as propylene, butylenes, amylenes, hexenes, etc.,

. may be obtained also by catalytic dehydrogenation of paraflins, by pyrolysis of certain paraffinic hydrocarbons, and by dehydration of alcohols.

In general, olefins have a relatively high from propylene and butylenes.

activity and even under mild catalytic influence they exhibit this activity by their pronounced tendency to polymerize and form substances of higher molecular weights. This process is particularly effective for converting propylene and butylenes into normally liquid polymers.

The present process is directed particularly to the production of polymers containing from about 6 to about l2 carbon atoms per molecule The preferred polymer products boil at temperatures within the approximate boiling range of commercial gasoline. These polymers containing from about 6 to about 12 carbon atoms per molecule are useful for blending with straight-run gasoline to increase its antiknock value.

By the addition of hydrogen cyanide to liquid hydrogen fluoride, the ordinarily vigorous reaction of hydrogen fluoride on catalytic condensation reactions among hydrocarbons .is moderated. Thus I have found that substantial yields of liquid polymers of relatively low molecular weights are produced when propylene and butylenes are reacted at a temperature of from about 30 toabout +130 C., but preferably at a temperature of from about20 to about C. in the presence of a catalyst comprising essentially a major proportion of hydrogen fluoride and a minor proportion of hydrogen cyanide. Such polymerization treatment is generally carried out at a pressure sufflcient to maintain the reacting hydrocarbons and catalyst in substantially liquid phase: Accordingly, the present invention deals with the modification of a hydrogen fluoride polymerization catalyst by the addition thereto of a particular non-oxidizing acid which moderates the action of hydrogen fluoride and modifies the polymerization reaction in. such a way as to improve the'yield and quality of relatively low boiling but normally 'liq'uidproducts.

Hydrogen cyanide is a weak volatile acid and like hydrogen fluoride it is a liquid at ordinary temperatures and at atmospheric or moderate superatmospheric pressures. Hydrogen cyanide has a boiling point of 26.5 C. and hydrogen fluoride boils at 19.4 C. The melting points of hydrogen cyanide and hydrogen fluoride are --13.4 C. and -92.3 C., respectively. Hydrogen cyanide is soluble in water, alcohol, and ether, and also in hydrogen fluoride at the conditions of reaction in the. concentrations which are contemplated in the present process. Ordinarily the catalyst employed in my invention may comprise from about 0.5 to about 10% by weight of hydrogen cyanide. Because of its toxicity and attendant dimculties when employed in high concentrations it is generally desirable to maintain the hydrogen cyanide content of the catalyst below about 5% by weight.

My polymerization process may be carried out in a batch operation but preferably in continuous type of operation. In batch type treatment an olefinic hydrocarbon or a hydrocarbon fraction a heavier. catalyst layer.

returned to the autoclave for use in another poly multiple polymerization reactor system is employed. a A

Continuous operation of my process may be carried out by passing a mixture of an oleflncontaining hydrocarbon fraction and a mixture 4. 2. A process for synthesizing oleflnic hydrocarjbons otgasoline boiling range which comprises polymerizing a normally gaseous olefln having at icast 3 carbon atoms per moleculein the presence oi a catalyst comprising a major proportion by weight of liquid hydrogen fluoride and a minor proportion of hydrogen cyanide.

of hydrogen fluoride and hydrogen cyanide through a suitable reactor. separating liquid.

polymers from unconverted oieflns and catalyst mixture and recycling the unconverted oleflnsand catalyst mixture to the polymerization zone of the process.

The following example is gi n t 5m f .1.- suits obtainable by the present process, although it is not intended to limit the scope of the invention in exact correspondence with the examp gen cyanide is placed in an autoclave of apie. A mixture of 143 grams of substantially anhydrous hydrogen fluoride and 5 grams of hydro- 3. A polymerization process which comprises contacting an oieilnic hydrocarbon having at least 3 carbon atoms per molecule at a temperature of from about to about +130 0. in the. presence of a catalyst comprising essentially a major proportion by weight of liquidhydrogen a minor proportion of hydrogen cyfluoride and snide.

.'4. A polymerization process which comprise contacting an oleflnic hydrocarbon having at least .3 carbon atoms per molecule at a temperature of from about 20 to-about 100 C. in the presence of a catalyst comprising essentially a major proportion by weight of liquid hy ro en fluoride and a proximately 2000 cc.-capacity equipped with a pressure-sealed stirrin device. The autoclave is maintained at approximately 75 C. while 1000 cc. of a liquid containing 2 molecular proportions or normal butane and 1 molecular proportion of normal butylene is introduced continuously to the autoclave ove a period oi 1.5 hours.

The resultant ixture of reaction products is separated into a hydrocarbon polymer layer and The used catalyst is merization run, while the hydrocarbon polymer layer is washed with water and alkali and then dried and lractionaliy distilled to separate a hr- 1 drocarbon lractionoi" gasoline boiling range containing a substantial proportion -01 branched chain octenes and polymers of higher molecular weights containing up to about 12 carbon atoms per molecule.

I claim asmy invention:

A polymerization process which comprises reacting an oieflnic hydrocarbon having at least 3 carbon atoms per molecule in the presence of a liquid'hydrogen fluoride catalyst to which has bee: added a minor proportion or hydrogen cyani e.

minor proportion of hydrogen cyanide.

5.'A polymerization process which comprises reacting propylene at a temperature or from about .20" to about C. in the presence of a,

liquid hydrogen fluoride catalyst containing a minor proportion 01' yd o en cyanide.

6. A polymerization process which comprises reacting butylene at a temperature of from about '20" to about 100 C. in the presence oi a. liquid hydrogen fluoride catalyst. containing a minor proportion of hydrogen cyanide.

. I. A polymerization process which comprises reacting propylene and butylene at a temperature 01' from about.20 to about 100 C. in the presence. of a liquid hydrogen fluoride catalyst containing a minor proportion of hydrogen cyanide. i

8. A polymerization process which comprises contacting an oieflnio hydrocarbon having at least 3 carbon atoms per molecule at a temperature of lrom about'20 to about 100 C. and at a pressure sufllcient to maintain in liquid phase a substantial proportion of the reacting oleflnic hydrocarbon and catalyst in the presence or a catalystoomprislng essentially amajor proportion by weight of liquid hydrogen fluoride and a minor proportion or hydrogen cyanide.- 

